1374408-76-0Relevant academic research and scientific papers
1,2,4-Oxadiazole 4-oxides as nitrones in 1,3-dipolar cycloaddition reactions to vinyl ethers
Quadrelli, Paolo,Lunghi, Fabio,Bovio, Bruna,Gautschi, William,Caramella, Pierluigi
experimental part, p. 1418 - 1425 (2012/04/05)
1,2,4-Oxadiazole 4-oxides display nitronic reactivity and selectivities identical to those of N-methyl-C-phenyl nitrone, which is a typical acyclic nitrone, affording comparable amounts of endo- and exo-5-alkoxyisoxazolidines. The exo stereoisomers undergo an easy rearrangement under the reaction conditions to yield oxadiazolinic esters. The structures of the adducts have been confirmed by X-ray structures and spectroscopic data. A donor p-methoxyphenyl at the nitronic carbon slows down the cycloaddition rate, while an acceptor p-nitrophenyl retards the rearrangement of the exo adduct. 1,2,4-Oxadiazole 4-oxides undergo 1,3-dipolar cycloaddition reactions with vinyl ethers to afford endo adducts and labile exo adducts that rearrange to oxadiazolinicesters. The structures of the isolated products were assigned on the basis of spectroscopic data and X-ray analyses. Copyright
